Chemical Characteristics of Selected Grass Species from Polish Meadows and Their Potential Utilization for Energy Generation Purposes

Comparative flooding tolerance of Typha latifolia and Phalaris arundinacea in wetland restoration: Insights from photosynthetic CO2 response curves, photobiology and biomass allocation

Tall helophytes such as Typha latifolia and Phalaris arundinacea often rapidly colonise after rewetting of former agricultural soil and are therefore often the first plants to contribute to the soil carbon pool. In this study we carried out a mesocosm experiment where these two species grew at three different water levels relative to the soil surface (-15 cm, 0 cm, +15 cm). After eight weeks' growth, measurements of photosynthetic CO2-response curves, stomatal conductance and chlorophyll fluorescence of photosystem II were carried out to detect flooding stress. After 10 weeks' growth, the plants were harvested and biomass production, biomass allocation and specific leaf area were determined. T. latifolia had a higher and more stable photosynthetic performance across all water level treatments, which resulted in an overall higher aboveground and belowground production than P. arundinacea. In contrast, Vcmax and Jmax decreased by 41 % and 42 %, respectively from drained to flooded conditions with signs of flooding stress as impairment of the photosynthetic apparatus. Moreover, increasing water level resulted in maintenance of aboveground organs for P. arundinacea but a decrease in allocation to belowground organs. P. arundinacea did not invest in a higher specific leaf area to counter the decreased photosynthesis under flooding. From -15 cm to 0 cm water levels, P. arundinacea showed a 68 % reduction in belowground biomass, which has negative implication for carbon retention immediately after rewetting. In contrast, recolonization of T. latifolia is likely to be a suitable contributor to the soil carbon pool due to its stable physiology and high above- and belowground biomass production at all water depths, and also likely under natural water level fluctuations. We showed that even though both species are generally considered wetland plants, they are likely to support considerably different photosynthetic carbon assimilation and soil carbon sequestration rates.

Climate vs Energy Security: Quantifying the Trade-offs of BECCS Deployment and Overcoming Opportunity Costs on Set-Aside Land

Bioenergy with carbon capture and storage (BECCS) sits at the nexus of the climate and energy security. We evaluated trade-offs between scenarios that support climate stabilization (negative emissions and net climate benefit) or energy security (ethanol production). Our spatially explicit model indicates that the foregone climate benefit from abandoned cropland (opportunity cost) increased carbon emissions per unit of energy produced by 14-36%, making geologic carbon capture and storage necessary to achieve negative emissions from any given energy crop. The toll of opportunity costs on the climate benefit of BECCS from set-aside land was offset through the spatial allocation of crops based on their individual biophysical constraints. Dedicated energy crops consistently outperformed mixed grasslands. We estimate that BECCS allocation to land enrolled in the Conservation Reserve Program (CRP) could capture up to 9 Tg C year-1 from the atmosphere, deliver up to 16 Tg CE year-1 in emissions savings, and meet up to 10% of the US energy statutory targets, but contributions varied substantially as the priority shifted from climate stabilization to energy provision. Our results indicate a significant potential to integrate energy security targets into sustainable pathways to climate stabilization but underpin the trade-offs of divergent policy-driven agendas.

Recent Advances in Miscanthus Macromolecule Conversion: A Brief Overview

Miscanthus is a valuable renewable feedstock and has a significant potential for the manufacture of diverse biotechnology products based on macromolecules such as cellulose, hemicelluloses and lignin. Herein, we overviewed the state-of-the art of research on the conversion of miscanthus polymers into biotechnology products comprising low-molecular compounds and macromolecules: bioethanol, biogas, bacterial cellulose, enzymes (cellulases, laccases), lactic acid, lipids, fumaric acid and polyhydroxyalkanoates. The present review aims to assess the potential of converting miscanthus polymers in order to develop sustainable technologies.

Range grasses to improve soil properties, carbon sustainability, and fodder security in degraded lands of semi-arid regions

Tropical grasses are the primary source of forage for livestock and a valuable resource for improving soil health and environmental sustainability in semi-arid regions. A study was carried out in a semi-arid region of central India to determine the short-term (6-year) impact of nine range grasses on soil physio-chemical and biological properties, carbon stock, and forage security. The experiment was carried out in a randomized block design with three replications. Results show that the majority of the grass roots were distributed in the upper soil layer (0-10 cm, 63.5-76.5 %), and then in the middle (10-20 cm, 21.3-25 %) and lower (20-30 cm, 2.2-11.5 %) layers. Perennial tussock grass (Heteropogon contortus (L.) P. Beauv. ex Roem. & Schult) had a higher root volume (2219 mm³), followed by Guinea grass [Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs] (1860 mm³). A lower soil bulk density (BD, 1.11-1.23 g cm^-3), higher gravimetric water content (GMW, 14.0-17.8 %), and soil organic carbon (0.38-0.73 %) were recorded for grass-cultivated plots compared to the barren land (1.38 g cm^-3, 13.0 %, and 0.28 %, respectively). The perennial tussock grass and Guinea grass resulted in the highest soil microbial biomass carbon (SMBC, 70.1 mg kg^-1 soil) and enzyme activities (dehydrogenase, 17.09 μg TPF g^-1 day^-1 and fluorescein diacetate activity 4.94 μg fluorescein g^-1 h^-1). The considerable improvement in soil properties with minimal inputs resulted in a higher sustainable yield index and carbon sustainability index in plots planted with Guinea grass (0.9 and 89.29) and perennial tussock grass (0.89 and 71.61). Therefore, the cultivation of either Guinea grass or perennial tussock grass as an intercrop or sole crop in the semi-arid environment can be an ecologically sound strategy to improve soil health, C sequestration, and fodder supply.

Isolation and Characterization of Natural Cellulose from Oxytenanthera abyssinica (Lowland Ethiopian Bamboo) Using Alkali Peroxide Bleaching Stages Followed by Aqueous Chlorite in Buffer Solution

Plants are the primary sources of cellulose. This paper is aimed at isolating cellulose from Oxytenanthera abyssinica via chemical treatments. The thermal behavior, functional group, chemical composition, crystallinity, and morphology of raw (ROA), dewaxed (DOA), alkali-treated (AOA), and bleached (BOA) fibers were examined. TGA, FTIR, DSC, DTA, XRD, and SEM were used for characterization techniques. The effects of chemical treatments were examined by determining the content of cellulose, hemicellulose, lignin, and ash. The cellulose content in the ROA improved from $49.26\pm 0.13$  wt% to $86.01\pm 0.02$  wt% due to the removal of noncellulose components using waxing, alkali treatment, and bleaching with alkali peroxide bleaching stages followed by aqueous chlorite in buffer solution. The highest content of cellulose and holocellulose was exhibited in the BOA samples with a yield of $86.01\pm 0.02$  wt% and $97.61\pm 0.17$  wt%, respectively. ROA had greater hemicellulose ( $21.31\pm 0.15$  wt%), lignin ( $20.63\pm 0.12$  wt%), and ash content ( $3.30\pm 0.11$  wt%) in comparison to AOA and BOA. The XRD data showed a change in crystallinity after each treatment. Because of the high amount of crystalline cellulose, the XRD results revealed that BOA has a higher crystallinity index (CrI) (59.89%) and peak intensity than AOA, DOA, and ROA. The strength of the FTIR peaks increased in the order of ROA, DOA, AOA, and BOA, indicating that pretreatment causes hemicellulose and lignin to be gradually removed from the Oxytenanthera abyssinica fiber. The TGA, DTG, DTA, and DSC data also confirmed that BOA has the highest thermal stability due to the high content of cellulose. The SEM analysis showed a morphological change in the surface due to chemical treatment. These results confirmed that through chemical pretreatment, a high amount of cellulose was produced from Oxytenanthera abyssinica. Even though Oxytenanthera abyssinica is commonly grown in Ethiopia, few studies have been done on it, and no works have been carried out to isolate and characterize cellulose from the plant. Thus, the findings in this work will encourage researchers to use Oxytenanthera abyssinica as a source of cellulose for various applications, including the manufacture of cellulose nanocrystals, polymer matrix biofilters, green biocomposite reinforcing agents, and hydrogel synthesis.

Optimizing Anthocyanin-Rich Black Cane (Saccharum sinensis Robx.) Silage for Ruminants Using Molasses and Iron Sulphate: A Sustainable Alternative

Anthocyanin-rich black cane (aBC) is a grass rich in lignin and carbohydrates, with an abundance of anthocyanins. Silages of aBC produced with molasses (MS) and/or ferrous sulphate (FS) mixtures may have beneficial effects on silage quality and animal performance in ruminants. However, the addition of MS and FS to ensiled grass is relatively unexplored. Therefore, this study systematically evaluated the effect of their administration at different doses to select an effective treatment to modulate the ensiling characteristics of aBC. In the first trial, fresh or pre-ensiled materials (PBC) were compared with ensiled PBC treated with: 0% MS 0% FS, 4% MS, 8% MS, 0.015% FS, 0.030% FS, 4% MS + 0.015% FS, 4% MS + 0.030% FS, 8% MS + 0.015% FS, and 8% MS + 0.030% FS on a fresh matter basis. The quality of ensiling characteristics was determined in laboratory-scale silos after 42 d of preservation. Based on these results, the second trial was further conducted in rumen cultures to ensure that the selected treatment would not impair rumen fermentation. For this, ruminal biogases, rumen fermentation profiles, and microbial communities were evaluated. Ensiled PBC with the incremental addition of MS and FS resulted in the observations for anthocyanin contents and the ensiling characteristics of the aBC silages. The combination of MS (4%) and FS (0.030%) incorporated into silages had the highest silage production effect among the experimental treatments. This combination demonstrated the sustainable mitigation of the ruminal biogases of methane and carbon dioxide without impairment of total gas production. Concurrently, this combination improved total volatile fatty acid concentrations, modulated cellulolytic bacteria, and suppressed methanogenic bacteria in rumen fluids. The results presented here indicated that addition of a mixture of 4% MS and 0.030% FS to aBC resulted in an optimal balance of ensiling characteristics and is suitable for use in ruminants.

Integrated Life Cycle Assessment Modelling of Densified Fuel Production from Various Biomass Species

This work presents new data on the life cycle impact assessment of various lignocellulosic biomass types in Mexico. A comparative life cycle assessment model of biomass densification systems was conducted. An integrated approach that incorporated various process variables, such as technology and variations in feed properties, within the analysis was employed to evaluate the environmental impact of producing 1 MJ of energy-containing densified fuel. The results show that the densification unit and curing (fuel drying) have the highest impact on the life cycle’s operational energy and the total life cycle energy, respectively. Of all the 33 biomass types from the 17 species sources considered in this study, sweet sorghum and sandbur grass have the highest global warming potential, 0.26 and 0.24 (kg CO2-eq), and human toxicity 0.58 and 0.53 (kg 1,4-dichlorobenzene-eq), respectively, while coffee pulp and cooperi pine wood have the least impact in both categories, with values of 0.08 and 0.09 (kg CO2-eq), and 0.17 and 0.16 (kg 1,4-dichlorobenzene-eq), respectively. Chichicaxtla sawmill slabs also have a low environmental impact, and cooperi pine and Ceiba wood have the lowest ozone depletion and ecotoxicity potential. A sensitivity analysis indicated the effects of the transportation system and energy source on the life cycle’s environmental impact. Adequate feed preparation, the blending of multiple feeds in the optimum ratio, and the careful selection of densification technology could improve the environmental performance of densifying some of the low-bulk-density feed biomass types.

Specific Methane Yield of Wetland Biomass in Dry and Wet Fermentation Technologies

Our study evaluated the specific methane yield (SMY) of selected wetland species subjected to wet and dry anaerobic digestion: Carex elata All. (CE), a mixture (~50/50) of Carex elata All. and Carex acutiformis L. (CA), Phragmites australis (Cav.) Trin. ex Steud. (PA), Typha latifolia L. (TL) and Phalaris arundinacea L. (PAr). Plants were harvested in late September, and therefore, the study material was characterised by high lignin content. The highest lignin content (36.40 ± 1.04% TS) was observed in TL, while the lowest (16.03 ± 1.54% TS) was found in CA. PAr was characterised by the highest hemicellulose content (37.55 ± 1.04% TS), while the lowest (19.22 ± 1.22% TS) was observed in TL. Cellulose content was comparable in almost all plant species studied and ranged from 25.32 ± 1.48% TS to 29.37 ± 0.87% TS, except in PAr (16.90 ± 1.29% TS). The methane production potential differed significantly among species and anaerobic digestion (AD) technologies. The lowest SMY was observed for CE (121 ± 28 NL kgVS−1) with dry fermentation (D–F) technology, while the SMY of CA was the highest for both technologies, 275 ± 3 NL kgVS−1 with wet fermentation (W–F) technology and 228 ± 1 NL kgVS−1 with D–F technology. The results revealed that paludi-biomass could be used as a substrate in both AD technologies; however, biogas production was more effective for W–F. Nonetheless, the higher methane content in the biogas and the lower energy consumption of technological processes for D–F suggest that the final amount of energy remains similar for both technologies. The yield is critical in energy production by the AD of wetland plants; therefore, a promising source of feedstock for biogas production could be biomass from rewetted and previously drained areas, which are usually more productive than natural habitats.

Mineral Contents in Aboveground Biomass of Sedges (Carex L., Cyperaceae)

The importance of mineral elements, both in animal and plant nutrition, has been well recognized, but, in the case of sedges, the mineral composition is relatively poorly known. Studies usually relate to the content of the elements in sedge communities, or sward or hay communities with sedge participation, and rarely of Carex representatives. The objective of our study was to determine the concentrations of C, N, Ca, P, Mg, Na, K, Si, Cu, Zn, Mn, Fe, Cr and Ni in the biomass of 11 Carex species commonly occurring on natural sites of Central European lowland. Interspecific differentiations have been observed in concentrations of the major and trace elements among studied sedge species. The elemental composition of examined Carex species is diversified but generally similar to the composition of grasses. The study shows that sedges can increase fodder value and, therefore, they should be considered in meadow management as a valuable component of economically important meadow communities. Moreover, the data reported herein can be used for modelling the phytoaccumulation of various elements in the biomass of sedges. This will help in creating different patches suitable for obtaining adequate fodder. Our results can supplement current knowledge concerning the fodder value of meadows with sedge participation.